Polymerization of poly(halostyrene) has been achieved using free-radical and anionic polymerization techniques.
Hayword et al. recently reported in Polymer Bulletin 18, 27 (1987), the results of some special types of radical polymerization methods for polymerizing p-chlorostyrene. However, these methods were unsuitable for making polymers with well defined molecular weights and/or molecular weight distributions.
Burnett et al. in Eur. Polym. J. 2, 329 (1966), reported the anionic polymerization of p-chlorostyrene. However, because of the chlorine unit on the aromatic ring, polymerization had to be carried out at extremely low temperatures and the polymer structure was not well-defined, indicating that the reaction did not proceed in a satisfactory manner.
The synthesis of chlorine-capped telechelic polymers by the inifer method has been described in great detail in the following references:
1. J.P. Kennedy and R.A. Smith, J. Polym. Sci., Polym. Chem. Ed. 18, 1523 (1980);
2. A Fehervari, J.P. Kennedy and F. Tudos, J. Macromol. Sci., Chem., A15(2), 215 (1981);
3. B. Ivan, J.P. Kennedy and V.S.C. Chang, J. Polym. Sci., Chem Ed., 18, 3177 (1980);
4. R.H. Wondraczek, J.P. Kennedy and R.F. Storey, J. Polym. Sci., Polym Chem Ed., 20, 43 (1982); and
5. R. Santos, A. Fehervari and J.P. Kennedy, J. Polym. Sci., Polym. Chem. Ed., 22, 2685 (1984).
These polymerization methods have also been the subject of numerous patents covering different types of polymerization aspects involving the inifer method:
Kennedy et al., U.S. Pat. No. 4,276,394
Kennedy et al., U.S. Pat. No. 4,316,973
For example, Kennedy in U.S. Pat. No. 4,276,394 disclosed the use of the inifer method to polymerize novel telechelic polymers having a chlorine terminus. These polymers involve the use of isobutylene as the polymerizable monomer and taught the use of other alpha olefins to form telechelic polymers terminating in chlorine groups using binifers as one type of initiator for the inifer polymerization method. However, in "Carbocationic Polymerization", John Wiley and Sons, New York (1982), Kennedy and co-workers indicated that the polymerization of p-chlorostyrene would be slow and difficult and would not be easily attainable.
Cationic polymerization of styrene type monomers has often been plagued with the problem of the formation of indane ring type end structures. The indane type ring system is formed by self alkylation of the aromatic ring by the cationic terminus. Indane ring systems are disadvantageous because the indane ring systems interfere with telechelic end group formation.
It thus appears to be desirable to manufacture a chlorine telechelic polymer based on poly(p-halostyrene) from the inifer method, especially chlorine terminated telechelic polymers based on halostyrenes which have little to no indane contamination. These polymers are useful because of their inflammability, their optical properties, and their chemical resistance properties. This makes them ideally suited for use in gaskets, in optically clear films that are thermally stable, oxidatively stable and inflammable and in other applications requiring inflammable, chemically resistant and/or optically clear films.